Hicks: He alone will feel gratitude towards friends, present and absent alike, and show it by word and deed.

Yonge: That the wise man will only feel gratitude to his friends, but to them equally whether they are present or absent.

Mensch: He alone will feel gratitude toward friends, present and absent alike.

Original text (with punctuation and letters from British Library manuscript): μόνον τε χάριν ἕξειν τὸν σοφόν καὶ ἐπὶ φίλοις· καὶ παροiσι καὶ ἀποiσιν ὁμοίως διά τε οδού

• Perseus has λόγου <καὶ διὰ πράξεως> but mentions οδού in a note.

μόνον does appear to refer to τὸν σοφόν, so "only the sage" can also carry the idea of “the sage is uniquely able,” so we're getting at the idea that the sage is uniquely qualifed to have thankfulness, gratitude "towards friends" whether present or absent at a distance (διά οδού)

I find it odd that this clause is sandwiched between two mentions of torture in the original text. Is this a scribal error? Does this one about friends reference something about the sage being tortured? The Perseus original text is identical to the digitized British Library manuscript as far as the placement of the three characteristics (i.e., torture 1 - gratitude - torture 2).